A silent chain is constructed such that engaging links, each composed of a set or plurality of piled-up link plates, are coupled by connector pins in an endless form. As disclosed in Japanese U.M. Publication No. Sho 57-59726, for example, there is illustrated a silent chain in which, as shown in FIG. 3 hereof, irregular links L' are provided having short engaging surfaces T' which are disposed inwardly from the engaging surfaces T of the standard links L by an amount e, and such links L' are irregularly arranged along the chain in order to reduce shock sound when the engaging teeth of the sprockets are engaged and further to disperse the shock sound generated during an engaging operation.
In the aforesaid prior art, although the shock sound generated during an engaging operation is dispersed by irregularly arranging the sets of irregular link plates having a short length between the engaging surfaces of the standard link plates in the longitudinal direction of the link plates, the irregular link plates having the short length between the engaging surfaces may generate a pulsation in driving of the chain due to the fact that the engaging time of the sprocket teeth is always delayed and at the same time as the engaging surface angles on all links are kept constant, resulting in the engaging surfaces of the sprocket teeth engaging with the engaging surfaces of the link plates at specified location so that wearing is concentrically generated only at the aforesaid specified location in the engaging surfaces of the sprocket teeth to cause the engaging surfaces of the sprocket teeth to be deformed, and thus this may prohibit a smooth engaging transmission or moving operation.
Accordingly, the present invention relates to an improved link arrangement, and resulting silent chain, which is believed to significantly improve the above problem.
The present device is constructed such that the engaging surface angles of the link plates are varied, with irregular links having different interengaging surface lengths in reference to a standard link plate being irregularly arranged in the longitudinal direction of the chain, whereby the engaging locations of the link plates with the engaging surfaces of the involuted sprocket teeth are dispersed over an entire region of the engaging surfaces of the sprocket teeth so as to avoid a concentration of the wearing only at specified locations, and at the same time the engaging time is delayed to prevent a pulsation of the chain so as to disperse the engaging shock sound and to keep a smooth engaged transmitting operation.
As the engaging surface angles of the irregular links are different, the engaging position with the engaging surface of the link is not concentrated at a specified location, but every time the engaging surface angles of the links are made different, the engaging locations with the sprocket teeth are moved, and extend over the entire region of the engaging surfaces of the sprocket teeth, resulting in a wearing action which is not concentrated at a specified location on the engaging surfaces of the sprocket teeth. In turn, if the length between the engaging surfaces of the irregular links is different so as to have a long length or a short length, the occurrence times of the engaging shock sounds with the sprocket teeth are dispersed and interfere with one another not only to cause a sound-silencing action, but also to cause delays in engaging times with the sprocket teeth are to prevent a pulsation driving of the chain from being attained.